Image pickup apparatus with vibration based camera control

ABSTRACT

An image pickup apparatus including image pickup device for photoelectrically converting an object image and generating an image pickup signal, a memory for storing the image pickup signal generated from the image pickup device, a detecting sensor for detecting a variation of the apparatus and a control circuit for storing a still image signal generated from the image pickup device to be stored in the memory in the case that the vibration detected by the detecting sensor is equal to or less than a predetermined value and for inhibiting storing of the still image signal to the memory in the case that the vibration is larger than the predetermined value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 08/697,915,filed Sep. 3, 1996, (abandoned), which is a continuation of Ser. No.08/431,575, filed May 1, 1995 (U.S. Pat. No. 5,568,190), which is adivisional of Ser. No. 08/105,778, Aug. 12, 1993 (U.S. Pat. No.5,469,210), which is a continuation of Ser. No. 07/843,916, filed Feb.27, 1992 (abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an image pickup apparatus such as a videocamera, video recorder of the camera integrated type, or the like.

2. Related Background Art

In an image pickup apparatus having an image pickup device forconverting an object image into an electric signal, for instance, in avideo tape recorder of the camera integrated type which has beenremarkably developed in recent years, various kinds of functions such asautomatic focusing, automatic iris, zoom, and the like are equipped asstandard functions. Further, functions to provide special effects suchas fetch of a still image by a digital memory, strobe effect, multiplexof characters or image, wipe, scroll, fade, and the like are alsoequipped. The video tape recorder of the camera integrated type has anextremely high quality with respect to the functions and operatingperformance.

FIG. 1 shows a schematic constructional block diagram of a conventionalexample. An image pickup device 10 generates an electric signal of anobject image. A camera signal processing circuit 12 converts the outputsignal of the image pickup device 10 into the video signal. An A/Dconverter 14 converts the analog video signal which is generated fromthe camera signal processing circuit 12 into the digital signal. Thedigital output signal is written into a memory 16 and is subjected tothe above special effects. The image data stored in the memory 16 isread out and returned into the analog signal by a D/A converter 18. Acontrol circuit 20 supplies sampling clocks to the A/D converter 14 andD/A converter 18 in accordance with the operation of an operation switch21 to instruct a special effect and also executes a digital signalprocess for the special effect using the memory 16. That is, the controlcircuit 20 allows the video signal which is generated from the camerasignal processing circuit 12 to be stored into the memory 16 inaccordance with the operation switch 21.

A switch 22 selects either the output of the camera signal processingcircuit 12 or the output of the D/A converter 18 in accordance with acontrol signal from the control circuit 20. That is, either the videosignal which is not subjected to the special effect or the video signalwhich has been subjected to the special effect is selected. The videosignal selected by the switch 22 is applied to a recording circuit 24and a monitor 26. The recording circuit 24 records the video signal ontoa recording medium such as a magnetic tape or the like. The monitor 26displays the image of the video signal.

By continuously connecting the switch 22 to the side of the D/Aconverter 18 to a certain degree, the display video image of the monitor26 and the recording video image by the recording circuit 24 are setinto a stationary state. The output video signal of the camera signalprocessing circuit 12 is intermittently stored into the memory 16. Byswitching the switch 22 to either the output side of the camera signalprocessing circuit 12 or the output side of the D/A converter 18 inaccordance with the data storage, the strobe effect is obtained.

However, the storage of the video signal which is generated from thecamera signal processing circuit 12 into the memory 16 is performed bythe control circuit 20 in accordance with the operation of the operationswitch 21 by the photographer. Consequently, there are drawbacks suchthat the video signal of the vibrated image is stored into the memory 16due to a shock, a hand vibration, or the like when the operation switch21 is operated, so that the picture quality of the still image based onthe still function, strobo function, or the like is lost.

On the other hand, generally, when the photographing by the video camerais considered, it must be considered that the camera vibration canobviously occur. The image stored in a state during the occurrence ofthe camera vibration becomes the image including the vibration even whenit is stored as a still image into the memory. Such a drawback becomes aseriously large problem, particularly, in the video camera tocontinuously photograph moving images for a long time instead of amomentary photographing as in the case of the still camera.

SUMMARY OF THE INVENTION

The invention is made to solve the above problems and it is the firstobject of the invention to provide a novel video camera in which thestorage of an image having a vibration into a memory can be preventedand an always preferable image can be generated.

The second object of the invention is to provide a photographingapparatus in which when an operation to instruct the storage of an imageinto a memory is performed, the image is stored into the memory at atime point when an influence by a vibration is small, thereby enabling astill image of a high quality without a vibration to be always obtainedfrom the memory.

To accomplish the above objects, according to a preferred embodiment ofthe invention, there is disclosed an image pickup apparatus comprisingan image pickup means; a memory to store an image signal generated fromimage pickup means; switching means for switching an output of the imagepickup means and an output of the memory; vibration detecting means fordetecting a vibration of an apparatus main body; and control means forallowing the image signal generated from the image pickup means to bestored into the memory when the vibration detected by the vibrationdetecting means is equal to or less than a predetermined value.

The third object of the invention is to provide an image pickupapparatus which has a function to correct a camera vibration even whensuch a vibration of the apparatus occurs and which can generate an imagewithout a vibration even when a vibration such that it exceeds acorrection limit and cannot be corrected occurs.

To accomplish the above object, according to a preferred embodiment inthe invention, there is disclosed an image pickup apparatus comprisingimage pickup means for photoelectrically converting an object image andgenerating an image pickup signal; memory means for storing the imagepickup signal generated from the image pickup means; switching means forswitching an output of the image pickup means and an output of thememory means; vibration detecting means for detecting a vibration of anapparatus main body; and control means for controlling the switchingmeans on the basis of an output of the vibration detecting means, forgenerating the image pickup signal generated from the image pickup meanswhen the vibration detected by the vibration detecting means is lessthan the predetermined value, and for generating the image signal storedin the memory means when the vibration detected by the vibrationdetecting means is equal to or greater than the predetermined value.

The above and other objects and features of the present invention willbecome apparent from the following detailed description and the appendedclaims with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a construction of a video camerahaving a general image memory;

FIG. 2 is a constructional block diagram of an embodiment of theinvention;

FIG. 3 is an operation flowchart of the embodiment;

FIG. 4 is a schematic constructional block diagram of the secondembodiment of the invention;

FIGS. 5A to 5C are side elevational views showing changes in apex angleof a variable apex angle prism 110;

FIGS. 6A and 6B are explanatory diagrams of operation characteristicsfor a vibration in a vibration correction limit;

FIGS. 7A and 7B are explanatory diagrams of operation characteristics ofa conventional example for a vibration exceeding a vibration correctionrange; and

FIGS. 8A to 8C are explanatory diagrams of operation characteristics ofthe embodiment for a vibration exceeding the vibration correction range.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be described hereinbelow withreference to the drawings.

FIG. 2 shows a schematic constructional block diagram of the firstembodiment of the invention. In FIG. 2, the same component elements asthose shown in FIG. 1 are designated by the same reference numerals.Reference numeral 30 denotes a vibration detecting circuit to detect thevibration of a camera and 32 indicates a control circuit to control thewriting and reading operations of the memory 16 and the switchingoperation of the switch 22 in accordance with the switching state of theoperation switch 21 and an output of the vibration detecting circuit 30,namely, a magnitude of vibration amount. The vibration detecting circuit30 generates a vector signal A indicative of an amount and a directionof the vibration to the control circuit 32.

The operation of the control circuit 32 will now be described in detailhereinbelow with reference to FIG. 3. First, when the operation switch21 is operated (step S1), the vibration signal A which is generated fromthe vibration detecting circuit 30 is fetched (S2). A magnitude |A| ofthe fetched vibration signal A is compared with a predetermined value A₀(S3). When the magnitude |A| of the vibration signal A exceeds thepredetermined value A₀ (NO in step S3), the fetch of the output of thevibration detecting circuit 30 is continued until the value of |A| isequal to or less than the predetermined value A₀ (S2, S3).

The predetermined value A₀ corresponds to the maximum vibration amountat which it is possible to regard that a vibration doesn't substantiallyoccur in the image. When there is a vibration exceeding the vibrationamount A₀, the vibration is conspicuous in the image, so that the imageis hard to see.

When the magnitude |A| of the vibration signal A is equal to or lessthan the predetermined value A₀ (YES in step 53), the A/D converter 14and memory 16 are made operative and the output video signal of thecamera signal processing circuit 12 is fetched into the memory 16 (S4).The switch 22 is switched to the side of the D/A converter 18. The videosignal stored in the memory 16 is repetitively read out and is suppliedto the recording circuit 24 and monitor 26 through the D/A converter 18and switch 22. Thus, the image in the still state is displayed on themonitor 26 and recorded onto the recording medium by the recordingcircuit 24.

By intermittently executing the special effect described here, a strobeeffect is derived.

As a vibration detecting circuit 30, it is also possible to use acircuit comprising a sensor to detect an angular acceleration, anangular velocity, an angular displacement, or the like and a processingcircuit for processing an output of the sensor and for generating avector signal or a circuit for digital signal processing an outputsignal of the image pickup device 10 or camera signal processing circuit12 and for obtaining an image motion vector.

As will be easily understood from the above description, according tothe invention, even when a vibration occurs in the apparatus due to theoperation to instruct the fetch of the image signal into the memorymeans, the data is fetched into the memory means when an adverseinfluence by the vibration is small. Therefore, the still image of ahigh quality without a vibration is derived from the memory means.Further, image data without a vibration can, be fetched into the memoryfor a special effect.

The second embodiment of the invention will now be described.

According to the above first embodiment, when the image signal iswritten into the memory, a state in which the vibration is equal to orless than a predetermined value is detected and the image signal isfetched into the memory so that the image without a vibration can becertainly stored. However, the following second embodiment furtherdiscloses an image pickup apparatus which can generate an image withouta vibration even for the occurrence of the uncorrectable image vibrationby using the memory.

That is, as mentioned above, the size and weight of the video camera arereduced since the solid state image pickup device has been put intopractical use. Interest in video cameras has increased because of therealization of its high magnification abilities and multi-functions. Inrecent years, the exposure control and focus control have been automatedand a failure in photographing which is caused due to those controls hasdecreased. However, the video camera is ordinarily used at a handgripped position, so that a possibility of hand vibration rises inassociation with the realization of the light weight andminiaturization. In the case of gripping the video camera by the hand,the screen is almost certainly vibrated. A deterioration of picturequality due to such a vibration of the screen and an unpleasantsituation for the viewer watching the video which may result inqueasiness or the like become problems.

As means for suppressing or eliminating such a screen vibration, aconstruction using a gyro mechanism or a construction using an opticaldecentering apparatus such as a variable apex angle prism or the like isknown. According to the former construction, the lens barrel system isstabilized by the gyro mechanism irrespective of the vibration of thephotographing apparatus main body. According to the latter construction,the optical axis of the photographing optical system is decentered bythe variable apex angle prism in such a direction as to set off thevibration of the photographing apparatus main body. The variable apexangle prism is constructed in a manner such that, for instance, theperipheries of two transparent plates which are away from each other inthe direction of the optical axis are closed by bellows and a liquid ofa predetermined refractive index is filled in the prism. Thephotographing optical axis is decentered by inclining the transparentplate on the object side for the surface which crosses perpendicularlyto the central axial line (optical axis at the neutral position).

The conventional example using the gyro mechanism has drawbacks of anincrease in size of the camera main body and an increase in weight. Onthe other hand, the conventional example using the variable apex angleprism has advantages such that an increase in size and weight of thecamera main body can be minimized because there is no need to constructthe lens barrel itself so as to have a movable structure.

However, in the vibration correcting apparatus using the optical axisdecentering means such as a variable apex angle prism, when a vibrationamount of the camera is large, there is a case where the vibrationamount exceeds the correction limit. For instance, the case where thecamera main body is vibrated at a proper period will now be considered.FIGS. 6A and 6B show the case where the camera main body is vibrated ina predetermined direction within the vibration correction limit. FIGS.7A and 7B show the case where the camera main body is vibrated byamounts exceeding the vibration correction limit. In FIGS. 6A and 7A, abroken line indicates the vibration correction limit by the variableapex angle prism and an alternate long and short dash line indicates theneutral position of the variable apex angle prism. In FIGS. 6A and 7A,reference numerals 40 and 42 denote vibrations of the camera main body.FIGS. 6B and 7B show vibrations of the photographed images in the casewhere the vibration corrections were performed for the vibrations 40 and42.

When the vibration of the camera main body lies within the vibrationcorrection limit, the photographed image doesn't vibrate but becomesstable in the screen as shown by reference numeral 44 in FIG. 6B. On theother hand, when the vibration of the camera main body exceeds thevibration correction limit, the photographed image doesn't vibrate asshown by reference numeral 46 in FIG. 7B for the vibration in thevibration correction limit as shown by reference numeral 46 in FIG. 7B.However, with respect to the portions (hatched portions 42A and 42B inFIG. 7A) exceeding the vibration correction limit, the vibrationscorresponding to the vibration amounts exceeding the vibrationcorrection limit appear on the photographed screen as shown by referencenumerals 46A and 46B in FIG. 7B.

That is, although the photographed image is stationary for the cameravibration within the vibration correction range, when there occurs acamera vibration exceeding the correction limit, the photographed imageis suddenly largely moved in the vibrating direction, so that anextremely unpleasant image change without a good quality picture occurs.

The embodiment intends to provide a photographing apparatus which cansolve such an inconvenience and discloses a video camera comprisingimage pickup means for photoelectrically converting an object image andgenerating an image pickup signal; memory means for storing the imagepickup signal generated from the image pickup means; switching means forswitching an output of the image pickup means and an output of thememory means; vibration detecting means for detecting a vibration of theapparatus main body; vibration correcting means for correcting thevibration on the basis of an output of the vibration detecting means;control means for controlling the switching means on the basis of theoutput of the vibration detecting means, for selecting the image pickupsignal generated from the image pickup means when the vibration detectedby the vibration detecting means lies within a range in which thevibration can be corrected by the vibration correcting means, and forgenerating the image signal stored in the memory means when thevibration detected by the vibration detecting means exceeds a limit atwhich the vibration can be corrected by the vibration correcting means;and recording means for recording an output of the switching means,wherein for the vibration exceeding the vibration correction limit byoptical axis decentering means, the just preceding image signal in thevibration correcting state which is stored into the image memory meansis selected, and a stable image without a vibration can be obtained evenwhen a vibration exceeding the vibration correction limit occurs.

FIG. 4 is a block diagram showing a construction of the video cameraaccording to the embodiment. In the diagram, reference numeral 110denotes a variable apex angle prism (VAP); 112 an actuator (e.g., coilwhich generates an electromagnetic driving force) to change an apexangle of the prism 110; 114 an angle sensor to detect the apex angle ofthe prism 110; 116 a photographing optical system; 118 an image pickupdevice to convert an optical image obtained through the prism 110 andoptical system 116 into an electric signal; 120 a camera processingcircuit for performing a well-known camera signal process such as gammaconversion or the like to the image signal which is generated from theimage pickup device 118 and for generating a video signal of thestandard format; and 122 an image memory which has a memory capacity ofone picture plane (one field or one frame) and stores the output videosignal of the camera processing circuit 120.

Reference numeral 124 denotes a switch to select either the output ofthe camera processing circuit 120 or the output of the image memory 122.The switch 124 is ordinarily connected to the output side (a contact) ofthe camera processing circuit 120. Reference numeral 126 denotes arecording circuit to record the video signal selected by the switch 124to a recording medium such as magnetic tape, magnetic disk, or the like,and 128 indicates a monitor to display a video image of the video signalselected by the switch 124. An electronic view finder of the videocamera can be also used in place of the monitor 128.

Reference numeral 130 denotes a vibration detecting sensor which isfixed to the lens barrel of the photographing optical system and detectsa vibration of the camera and 132 indicates a vibration correctioncontrol circuit to control the whole vibration correction of theembodiment.

FIGS. 5A to 5C are side elevational views of the variable apex angleprism 110. FIG. 5B shows a neutral state in which the apex angle isequal to 0. FIGS. 5A and 5C show vibration correction limits. When theapex angle increases to about an angle as shown in FIG. 5A or 5C, theapex angle cannot be increased beyond the above angles (that is, theoptical axis eccentric amount cannot be increased) and reaches thevibration correction limit.

The operation when the vibration correction is not performed is asfollows. The optical image which is derived through the prism 110 andphotographing optical system 116 enters the image pickup device 118. Theimage pickup device 118 photoelectrically converts the optical imageinto the image signal and generates the image signal. The cameraprocessing circuit 120 executes a well-known camera signal process tothe image signal and generates the video signal of a predeterminedformat. The output video signal is supplied to the a contact of theswitch 124 and to the image memory 122. The image memory 122sequentially updates the stored image. The switch 124 is generallyconnected to the a contact side and the output video signal of thecamera processing circuit 120 is supplied to the recording circuit 126and monitor 128 through the switch 124. The recording circuit 126records the input video signal onto a magnetic tape or the like inaccordance with an instruction of the photographer. The monitor 128displays the video image of the input video signal.

When the vibration correction is made operative, the following operationis executed. That is, the vibration detecting sensor 130 generatessignals indicative of the amount and direction of the camera vibrationand sends to the vibration correction control circuit 132. The anglesensor 114 generates a signal indicative of the apex angle of the prism110 and sends to the vibration correction control circuit 132. The anglesensor 114, vibration correction control circuit 132, and actuator 112form a closed loop to control the apex angle of the prism 110. For thecamera vibration within the vibration correction limit range, thecontrol circuit 132 calculates the eccentric amount and direction of thephotographing optical axis such as to set off the camera vibration andcontrols the actuator 112 so as to change the apex angle of the prism110 so as to provide such an eccentric state. As shown in FIG. 6B, astable photographed image which is not influenced by the cameravibration can be obtained.

For the camera vibration exceeding the vibration correction limit, thefollowing operation is executed. As for the vibration exceeding thevibration correction limit of the prism 110, the photographed imageoscillates according to the camera vibration as shown by hatchedportions 50A and 50B in FIG. 8A. The control circuit 132 switches theswitch 124 to a b contact at a timing (shown by reference numeral 52 inFIG. 8A) exceeding the vibration correction limit and inhibits thewriting operation (updating) of the image memory 122 and starts thereading operation from the image memory 122. The apex angle of the prism110 is held unchanged. FIG. 8B shows a control timing signal 56 for theswitch 124 and image memory 122. Thus, the video signal of the imagewhich is stored into the image memory 122 is transmitted to therecording circuit 126 and monitor circuit 128 through the switch 124, sothat a still image without the camera vibration is visually obtained asshown in FIG. 8C.

The switching operation of the switch 124 and the control of the imagememory 122 are obviously performed synchronously with the synchronoustiming of the video signal which is generated from the camera processingcircuit 120. Actually, they are executed at proper timings before thecamera vibration exceeds the vibration correction limit.

When the camera vibration is returned into the vibration correctionlimit range from a state in which it exceeds the vibration correctionlimit, the switch 124 is switched to the a contact side at a propertiming (54 in FIG. 8A) within a vibration correction limit range and thevibration correction by the prism 110 is restarted. The writingoperation (updating) of the image memory 122 is permitted. At thisstage, the photographed image becomes stable by the vibration correctionby the prism 110 irrespective of the camera vibration.

By the above control, as shown by a straight line 58 in FIG. 8C, thephotographed image is also stabilized even in the camera vibratingportion exceeding the vibration correction limit and the photographedimage which is always stable as a whole can be derived. For a period oftime during which the camera vibration exceeds the vibration correctionlimit, the video signal of the same image is supplied to both of therecording circuit 126 and the monitor 128. However, such a period oftime is generally an extremely short time like an instantaneous time andit is considered that such a period of time is not conscious in manycases, so that no problem occurs. A visual influence is smaller ascompared with that in the cases of the sudden movements as shown by thehatched portions 46A and 46B in FIG. 7B.

In the embodiment, the image signal after it was processed by the cameraprocessing circuit 120 is stored into the image memory 122 and the imagesignal stored in the image memory 122 is selected for the vibrationexceeding a predetermined vibration. The invention, however, is notlimited to the above case but a similar effect can be also obtained byproviding circuits similar to the image memory 122 and switch 124 at theoutput stage of the image pickup device 118 or for the signal in thecamera processing circuit 120 or the like.

As will be easily understood from the above description, according tothe invention, even when there is a vibration exceeding the limit of thevibration correcting capability, the photographed image in which a senseof disorder is visually small is obtained.

What is claimed is:
 1. An image pickup apparatus comprising: (A) imagepickup means for photoelectrically converting an object image andgenerating a moving image signal; (B) memory means for storing a stillimage signal; (C) instruction means for instructing a storing operationof storing the still image signal in said memory means; (D) detectingmeans for detecting a vibration of said apparatus; and (E) control meansfor extracting the still image signal from the moving image signal inresponse to an instruction of said instruction means and storing a stillimage signal in the memory means in the case that the vibration detectedby said detecting means is equal to or less than a predetermined valuewhen the instruction means is operated and for inhibiting storing of thestill image signal in the memory means in the case that the vibration islarger than the predetermined value when the instruction means isoperated.
 2. An apparatus according to claim 1, wherein said detectingmeans generates a vector signal indicative of a vibration amount and avibrating direction.
 3. An apparatus according to claim 2, wherein saiddetecting means is an external sensor unit for detecting angularacceleration, angular velocity, angle displacement, or the like.
 4. Anapparatus according to claim 2, wherein said detecting means is a motiondetecting circuit for digital signal processing the moving image signaland detecting a change in image and detecting the vibration.
 5. Anapparatus according to claim 1, further comprising recording means forrecording outputs of said image pickup means and said memory means. 6.An image processing apparatus comprising: (A) image output means forreceiving image information and generating an image signal; (B) memorymeans for storing the image signal generated from said image outputmeans; (C) instruction means for outputting an instruction signal forinstructing a storing operation of storing the image signal in saidmemory means; (D) monitor means for displaying the image signal on amonitor screen; (E) detecting means for detecting a vibration componentin the image signal which is generated from said image output means; and(F) control means for inhibiting output of the image signal output fromsaid image output means to said monitor means and the storing operationof said memory means and allowing output of a still image signal fromsaid memory means to said monitor means in the case that the vibrationcomponent detected by the detecting means is larger than a predeterminedvalue when said instructions means is operated.
 7. An apparatusaccording to claim 6, wherein said image output means is an image pickupdevice.
 8. An apparatus according to claim 6, wherein said control meansincludes switching means for switching the image signal which is outputfrom said image output means and the image signal which is output fromsaid memory means.
 9. An apparatus according to claim 8, furthercomprising recording means for recording an output of said switchingmeans.
 10. An image stabilizing apparatus comprising: (A) image pickupmeans for photoelectrically converting an object image and generating animage pickup signal; (B) memory means for storing a still imageextracted from the image pickup signal generated from said image pickupmeans; (C) detecting means for detecting a vibration of the apparatusmain body; (D) correcting means for correcting the vibration on thebasis of an output of the detecting means; and (E) control means forinhibiting a storing operation of the still image in said memory meansin the case that the vibration detected by said detecting means exceedsa limit at which said vibration can be corrected by said correctingmeans.
 11. An apparatus according to claim 10, wherein when thevibration detected by said detecting means exceeds the limit at whichsaid vibration can be corrected by the correcting means, said controlmeans stops the correcting operation of said correcting means.
 12. Anapparatus according to claim 10, wherein said correcting means isoptical vibration correcting means using a variable apex angle prism.13. An image processing method comprising: an image signal generatingstep of receiving image information and generating an image signal: astoring step of storing in memory means, the image signal generated insaid image signal generation step; an instruction step of outputting aninstruction signal for instructing a storing operation of storing theimage signal in said memory means; a displaying step of displaying theimage signal on a monitor screen; a detecting step of detecting avibration component in the image signal which is generated in said imagesignal generating step; and a controlling step of inhibiting output ofthe image signal output in said image signal generating step to saidmonitor screen and the storing operation of said storing step andallowing output of a still image signal from said memory means to saidmonitor screen in the case that the vibration component detected in saiddetecting step is larger than a predetermined value when saidinstruction step is performed.
 14. A method according to claim 13,wherein said controlling step includes a switching step of switching theimage signal which is output in said image signal generating step andthe image signal which is output from said memory means.
 15. A methodaccording to claim 14, further comprising a recording step of recordingan output of said switching step.